Reports: Fire at Nigeria's Warri oil refinery

Spokeswoman Tumini Green of the Nigerian National Petroleum Corp. said Tuesday morning's fire caused no injuries and was promptly extinguished.

But a statement purporting to come from the Movement for the Emancipation of the Niger Delta, or MEND, warned the fire is part of a new campaign against the government's "unsustainable and fraudulent" amnesty program.

Top MEND fighters signed a 2009 deal in which many were paid by the government. Some now provide protection for the international oil companies they used to attack.

But some disgruntled MEND activists threaten continued sabotage.

Relative peace holds though experts estimate Nigeria loses some 200,000 barrels of oil a day to theft by activists and criminals.